I have a 2000 Pontiac Grand Prix that recently the floor on the front passenger side is wet. The first time there was about 1 inch of standing water in it - and it was after a really bad rainstorm. The car was parked at an angle - front end high. About a month later the floor was really wet but did not have standing water and there had not been any rain in days. It is definitely fresh water - no antifreeze or windsheild fluid or anything like that, so we're not sure where it's coming from.

When we first bought the car - we had a problem with the evaporator case drain plug clogging up and the floor on the front passenger side was wet and it was under warranty the dealer fixed it, and we have not had a problem since then.

If someone can tell us where the evaporator case drain plug is we could check that to be sure it's not clogged up again.

If anyone has any ideas/suggestions - we're thinking it might be a hole in the firewall or something...maybe someone knows of a service bulletin on this one...we'd rather not spend alot of money if we don't have to.


Thank You.

 

Definitely check the drain first. Should be able to locate it by looking at the firewall from inside the engine compartment on the pax side. It will be a rubber tube about 1/2-3/4" diameter and maybe 6" long coming through the firewall and hanging down. You may need to look from underneath - use jack stands or ramps. Easiest way to clean it is to suck it out with a shop vac.

 

This is a long shot but if you have a sunroof, check it if it drains correctly. There should be a drain tube running from the sunroof to a wheel well. Also, using a hose, try and duplicate the problem. By concentrating the stream of water in various places on the car (fire wall, etc) you might be able to at least track down where the water is coming from.

I'm just a DYI mechanic so take my free advice for what it's worth.
JAB

 

i normally fix external water leaks by taking it out the back, making sure the area is that leaks is dry, getting inside, close doors and windows and get up under the dash and take parts out if necessary and get someone to squirt water all over the elft front of the car and watch for where it leaks. if it is as bad as you say it wont take long until you start seeing water come in, this way has worked for me 99% of the time.

 

If you also remove the plastic which is under the passanger wiper, you may find a piece of plastic may have come lose - the piece of plastic is used to dirvert water from the fan housing. I have a 1997 and had the same problem until I reinstalled the plastice. Hope this makes sense - let me know if you need to ellaborate..